The existing anti-virus systems are relatively slow to respond to the emergence of new viruses. This is due to the professional character of the virus attacks, the growing sophistication of the virus code and the fast development of new viruses. The systems are vulnerable because it takes time to detect the new virus code in the infected files, to study how it works and to develop new virus removal modules for the virus scanners. It also takes time to deliver simultaneously large numbers of copies of the virus scanner update patches to the clients, what also consumes the bandwidth of the network nodes. The fact that this has to be done constantly over and over again makes the things worse. In addition in the client side there may be unwillingness or carelessness to allow the virus scanner to check for new virus updates as frequently as it should be done, or to have all the downloaded files to be scanned by the virus scanner for old—let alone new viruses. It is not either uncommon to neglect obtaining a virus scanner. And even if a virus scanner is in use, its user may be perplexed by the complex and confusing scanning options. In addition it takes time to publicize the new virus discoveries in the organizations because of public relations reasons. The existing systems also waste processing power of network servers and home computers, because they require that each downloaded file is scanned for viruses. This is exacerbated by the rapid pace which the virus signature databases are growing in size.
The present invention was developed in order to overcome these problems with an efficient and well-organized Internet based anti-virus system which is capable to quickly response to the threats posed by new viruses. The introduced anti-virus system frees the network servers and home computers from redundant virus scanning by centralizing the virus combating functions. The centralization guarantees that the information about new viruses is immediately benefiting all the clients belonging to the system, and because of the architecture of the system a mere detection of an infected file is enough to impose an instant internet-wide download blockage for it without having to wait for the development and distribution of the virus removal modules for virus scanners. At the core of the system, the detection of the infected files is based mainly on the comparison of tiny-sized file identifications, wherefor no bandwidth or processing power is wasted. The system also lowers the barrier for the organizations to disclose the suspected new virus infections, because it has not necessarily to be done publicly but can simply be done to a central anti-virus host computer anonymously.